CHLAMYDIAE IN PORCINE ABORTION

Formalin-fixed, paraffin-embedded fetal livers and lungs from 139 case s of swine abortion were investigated retrospectively for chlamydiae b y means of immunohistochemistry. Using a genus-specific antibody, chla mydial antigen was found in eight livers obtained from five (3.6%) abo rtion cases from different herds. All lung sections were negative. Chl amydiae were also labeled in five of the eight positive livers using a monoclonal antibody against immunotype 1 of Chlamydia psittaci; the r emaining three livers were negative. No reactivity was seen using an a ntibody specific for C. trachomatis. Chlamydiae should be considered a cause of abortion in sows in Switzerland. Porcine abortigenic strains identified in this study differed immunologically from intestinal str ains (known to be mainly C. trachomatis) but shared similarities with abortigenic chlamydiae of ruminants.